Diffusion based metal oxide gas sensor
AssigneeSensirion AG
InventorsLukas BURGI, Frank ROCK
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Abstract
A measuring device is provided for determining the type and/or concentration a gaseous analyte from a set of analytes in a gaseous carrier. It comprises a housing having a passage to a cavity. A gas sensor with a heated metal-oxide sensing layer is arranged in the cavity. In order to gain a better understanding of the type of the analyte, diffusion effects are exploited by taking into account that the diffusion process through the passage as well as the catalytic reaction rate at the metal-oxide sensing layer depend on the type of the analyte. These material parameters can be determined by taking several measurements in a non-steady state of the concentration of the analyte within the cavity or while varying the reaction rate.
Claims17
A method for determining a type and/or concentration of an analyte from a set of analytes comprising the steps of
- providing a measurement device having
- a housing,
- a cavity within said housing,
- a gas sensor comprising a metal-oxide sensing layer and a heater for heating the sensing layer, and
- a passage extending between the cavity and the outside of the housing,
- heating the metal-oxide sensing layer, thereby generating a condition where said analyte is catalytically decomposed with a reaction rate k at said metal-oxide sensing layer,
- taking at least two measurements on said metal oxide sensing layer indicative of a concentration of said analyte, wherein the measurements are taken
- during a phase where a concentration cAV of the analyte within the cavity is in a non-steady state and/or
- for different reaction rates k, and
- deriving at least one material parameter indicative of the analyte from said measurements.
Dependencies are inferred from the claim text.